I stayed at Koy's place for one week and found it exactly as described.
Check-in and check-out were both smooth, very quick and flexible time-wise, which was favorable in my case. All the staff were very friendly at all times :).
The place is in a safe part of town and close to several embassies; I could walk home after midnight and was never bothered or felt uncomfortable.
The room itself was very clean and spacious - I enjoyed having the whole space available. There were extra amenities provided, like: shower gels, tooth brush, soap, shaving utility, hair-dryer, pocket WiFi, extra mattress, etc. The fully functional kitchen was equipped with the necessary utensils to cook full meals.
Parking lots are available on the ground floor, which is very convenient, if you have a car or anyone needs to come visit you by car.
The location is very central and close to the BTS Ploenchit station, about a 10' relaxed walk on foot.
Possible downsides, although irrelevant to me:
- flat is just in front of motorway (earplugs are provided)
- WiFi is slow compared to broadband internet (fast enough for Emails and Browsing)
Although I did not have the opportunity to meet the host in person, Koy kept in touch to make sure my needs were met and responded swiftly to any request I had.
I definitely recommend this place.